to an \(\mathbb {E}\) -extension \(\delta \in \mathbb {E}(C, A)\) . This \(\mathfrak {s}\)  is called a realization of \(\mathbb {E}\) , if it makes the diagram in [1]} commutative.
A triplet \((\mathcal {C}, \mathbb {E}, \mathfrak {s})\)  is called an extriangulated category if it satisfies the following conditions:
